As part of their latest attempt to block President Donald Trump’s travel ban, Senate Democrats say the order preventing refugees from Muslim-majority countries is being used by ISIS to recruit lone-wolf terrorists.

Eight Democratic senators on Friday introduced the No Ban on Refugees Act, which would prohibit the U.S. government from barring refugees from coming into the U.S. based on their country of origin.

“Trump’s refugee ban puts American lives at risk and it plays right into the hands of our enemies,” the bill’s lead sponsor, Senator Chris Murphy of Connecticut, said in a statement. “There’s no real danger to America from refugees who’ve gone through our vetting system and entered our country. The danger is that we help ISIS recruit lone-wolf terrorists here at home by making clear that they have no place in our society.”

Trump has used terrorist incidents across the world—most recently the attack in New York City on October 31—to justify his ban, which critics deem anti-immigrant and discriminatory.

“I have just ordered Homeland Security to step up our already Extreme Vetting Program,” Trump tweeted after an Uzbek immigrant killed eight people in lower Manhattan in what authorities called a “lone-wolf” attack.